Fast encoder decision for texture coding in 3D-HEVC Na Zhang a,n , Debin Zhao a , Yi-Wen Chen b , Jian-Liang Lin b , Wen Gao a a Department of Computer Science and Technology, Harbin Institute of Technology, Harbin 150001, China b MediaTek, No. 1, Dusing Rd. 1, Hsinchu 30078, Taiwan article info Article history: Received 6 March 2014 Received in revised form 6 June 2014 Accepted 6 June 2014 Keywords: 3D video coding Early merge mode decision Early CU splitting termination Inter-view correlation 3D-HEVC abstract As a 3D extension of the High Efficiency Video Coding (HEVC) standard, 3D-HEVC is developed to improve the coding efficiency of multi-view video. However, the improve- ment of the coding efficiency is obtained at the expense of a computational complexity increase. How to relieve the computational burden of the encoder is becoming a critical problem in applications. In this paper, a fast encoder decision algorithm to encode the dependent texture views is proposed, where two strategies to accelerate encoder decision by exploiting inter-view correlations are utilized. The first one is an early merge mode decision algorithm, and the second one is an early CU splitting termination algorithm. Experimental results show that the proposed algorithm can achieve 47.1% encoding time saving with overall 0.1% BD-rate reduction compared to HTM (3D-HEVC test model) version 7 under the common test condition (CTC). Both of the two strategies have been adopted into the 3D-HEVC reference software and enabled as a default encoding process under CTC. & 2014 Elsevier B.V. All rights reserved. 1. Introduction In recent years, 3D video is attracting more and more attention since users can experience realistic 3D scenes and select viewpoints interactively. Different 3D video formats or representations for delivering 3D video in applications have been designed. Texture-only formats such as conventional stereo video (CSV) and multi-view video (MVV) were first investigated. However, the bit-rate for transmission of 3D video with the texture-only format increases approximately linearly with the number of coded views. Thus, it is not feasible for transmission of a multitude of video views suitable for multi-view displays. After that, 3D video formats with few texture views and associated depth information which are also termed as MVD formats were investigated. The depth view is much easier to encode than the texture view. Based on the coded texture and depth maps, all necessary views for any 3D display can be generated, e.g., by means of depth-image- based rendering (DIBR) techniques [1]. However, for the MVD format, the multiple video sequences captured at different views and their associated depth maps still require a large storage space and a high transmission bandwidth. Therefore, an efficient 3D video compression standard is needed. As a 3D extension of the High Efficiency Video Coding (HEVC) [2], 3D-HEVC [3] with the primary focus on efficient compression of multi- view video is being developed by the Joint Collaborative Team on 3D Video Coding (JCT-3V), the joint working group of MPEG and ITU-T VCEG. Since all cameras capture the same scene simultaneously from different viewpoints, multi-view video data contains plenty of inter-view redundancies. Block based disparity- compensated prediction (DCP) is employed to exploit inter- view correlations. In addition to DCP, 3D-HEVC also integrates Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/image Signal Processing: Image Communication http://dx.doi.org/10.1016/j.image.2014.06.003 0923-5965/& 2014 Elsevier B.V. All rights reserved. n Corresponding author. E-mail addresses: hitnzhang@hit.edu.cn (N. Zhang), dbzhao@hit.edu.cn (D. Zhao), yiwen.chen@mediatek.com (Y.-W. Chen), jl.lin@mediatek.com (J.-L. Lin), wgao@jdl.ac.cn (W. Gao). Signal Processing: Image Communication ] (]]]]) ]]]–]]] Please cite this article as: N. Zhang, et al., Fast encoder decision for texture coding in 3D-HEVC, Signal Processing-Image Communication (2014), http://dx.doi.org/10.1016/j.image.2014.06.003i